Above 800 or 900 ft, the weather was often different. One day, there were 40 mph winds at the top but not at the base. Another, it snowed only on high. Once, the top was in a rain cloud. "We had to guarantee the schedule with no idea of what was going to happen with the weather," says LL's Peters.

At high altitudes, it's not just the weather that can get turbulent. With so much pressure and so many parties involved for more than three years, there were many battles, says Peters.

"We were dealing with some rough individuals," especially for the superstructure, Peters adds. "Every day ended with a screaming match."

Peters says his biggest lesson learned on the job is to pay closer attention to group and individual dynamics. "We had to learn to deal with the same people in an intense atmosphere for a longer period than on most projects," he says.

LL may get a chance to apply that lesson and then some. The construction manager is gearing up for four more Manhattan supertowers. At 1,775 ft, the tallest would dwarf 432 Park Avenue.